Now Nvidia and Microsoft are the best of chums, thanks to X-Box, the 3D graphics specialist's technology is beginning to appear in DirectX, Microsoft's games-oriented API. The first contribution is Nvidia's Volume Texture Compression (VTC) format, which doesn't sound much but gives a very tasty hint about the direction Nvidia is taking the X-Box's graphics engine. The key word here is 'volume'. The latest generation of 3D engines - with one exception, Mitsubishi's VolumePro chip - form object models out of matrices of points. The network of points define a surface over which a texture can be wrapped. That's fine as it goes, and greater external detail can be added by upping the number of points that define the model. The trouble is, this approach provides no information about the space within the model. Real objects, after all, tend to be solid - current 3D models aren't. That's why many 3D games developers - most notably iD Software's John Carmack - reckon that the next level of sophistication 3D games can achieve is to work with volumetric rendering. Models are constructed from layers of 2D data, rather like the way a series of 2D brain scans can be stack up to form a 3D model of the organ. The idea here is that when you frag a guy in Quake IV, blowing him in two, you won't just get a mess of blood, you'll be able to see the dude's internal organs. You can also do clever stuff like removing a character's skin, muscles, organs, right down to the bone, without having to generate a separate 3D model and texture for each view. Gross, yes, but that's what the kiddies like these days. Clearly Nvidia's development efforts have been thinking along these lines. The trouble with volumetric data is that each layer in the model is a texture, and that can mean the entire Strogg Tank (or whatever) will take up a heck of a lot of RAM. Each texture slice can be compressed individually using established techniques, such as S3's S3TC scheme (already a part of DirectX) and 3dfx's open source FXT format, but that still requires mucho memory. Presumably VTC also includes some kind of stack compression - if a pile of layers are identical, you only need to store the layer once. The upshot of all this for the X-Box is that by basing its 3D engine around a volumetric rendering system, it should be able to display very detailed 3D models indeed, something that's key to delivering Bill Gates' promise of "better than PlayStation 2" graphics. The actual on-screen rendering of the volumetric data can be handled by a regular 3D graphics chip, such as Nvidia GeForce 256, which is how Mitsubishi's VolumePro products actually get the volumetric numbers they've crunched onto the system's monitor. VTC will ship later this year, though Nvidia hasn't given a specific date. Whether it will remain an 'X-Box only' technology remains to be seen, but it seems unlikely - why make such a big deal about its incorporating into DirectX, if that were the case? Besides Microsoft wants X-Box to play PC games better, it doesn't want X-Box replace the PC altogether, so it makes sense to get this kind of technology out into the desktop 3D world too. That suggests Nvidia next chip - or maybe the next-but-one - will support volumetric rendering. One more thing. One Tony Barkans, Microsoft's program manager for DirectDraw, said in a statement that VTC will bring "stunning 3D graphics to Internet users". Look beyond the hyperbole, and Barkans' comment suggests that Microsoft is also planning to incorporate a WildTangent-style 3D metaformat into DirectX. WildTangent allows complex 3D Web graphics to be described in a relatively simple way, the upshot being that the Web site can send 3D information to a browser without gobbling up bandwidth - a browser plug-in uses client-side DirectX-compatible hardware acceleration to do the rendering. Curiously, WildTangent (the company and the software it offers) is the brainchild of one Alex St.John who just so happens to be one of Microsoft's original DirectX development leads. Could Microsoft's DirectX equivalent be a licensed version of WildTangent? It's certainly plausible, but unlikely since it appears St.John's parting of the ways with the Beast of Redmond may not have been amicable. In any case, Microsoft once had a scheme of its own to do something similar. Called Chromeffects, it was announced with much fanfare in 1998 only to be canned less than a year later. Time for a reincarnation, perhaps? ® Related StoriesNvidia NV15 to clock to 200MHzNvidia's Virtual AGP designNvidia gets $200m X-Box injectionX-Box unleashed: MS snubs PC OEMs, dumps AMD AthlonWill X-Box win (X) Windows Everywhere for MS?WildTangent to simplify DirectX game creation